Selector switch



Jan, 20,

J L. M QUARRIE ET AL SELECTOR SWITCH Filed Dec; 22, 1920 r\||| II I III lnverziors James AM Quarrze Char/a5 L. Goodrum.

TES

JAMES L. MGQUARRIE AND CHARLES L. GOODRUM, OF NEW YOR insane N. Y., ASSIGNOBS T WESTERN ELECTRIC COMPANY, INCORPORATED, 033 NEW YORK, N. Y., A. COR- ?ORATION OF NEW' YORK.

SELECTOR SWITCH.

Application filed December 22, 1920. Serial No. 432,417.

To all whom it may concern Be it known that we, JAMEs L. MOQUAR- inn and CHARLES L. GooDRUM, citizens of the United States, residing at New York, in the county of New York, State of New York, re-

spectively, have invented certain new and useful Improvements in Selector Switches, of which the following is a full, clear, concise, and exact description.

This invention relates to selective switches and particularly to switches of the type used in automatic telephone exchange systems.

The object of the invention is the provision of a switch in which a common operating and control mechanism for operating each of a plurality of brush sets is associated with the proper set of brushes in accordance with the particular path over which a connection is extended to the switch.

Other objects and advantages of the invention will become more apparent from a consideration of the following description.

In the drawing there is shown an auto matic selective switch used in the establishment of telephone connections from one subscribers line to another. This switch consists of two sets of independently operable brushes mounted on brush shafts 141 and 183 and adapted to be driven in a step-by-step 3o manner by a common operating magnet 129. The upper set of brushes 142, 143 and 144, mounted on the shaft 141, are arranged to engage the upper side of the contacts in the arcuate row, generally designated at 152. The lower set of brushes 149, 150 and 151, mounted on the brush shaft 183, are. arranged to engage the lower surfaces of the contacts in the row 152.

Connections are extended to the multibrush switch over two different paths or links. One of these links 184, 185 leads from the terminals 103, 104 at a preceding switch and terminates in the brushes 142, 143 of the upper set. The other of these links 186, 187 leads from the terminals 168, 169 and terminates in the brushes 150, 151 of the lower set of brushes. The terminals 103, 104 and 168, 169 are preferably located in the same switch and are so relatively positioned that calls incoming to the switch having access to these terminals will be directed over the link 184, 185 provided such link is idle in preference to bein extended over the second link 186, 187 Ifbwever, if the first link is busy at the time a connection is extended to the preliminary switch, then the first set of terminals 103, 104 will be found busy and the terminals 168, 169 selected to extend the connection over the lower link circuit 186, 187 to the lower brush unit shown in the drawing. As shown, the terminals 103, 104 appear in the contact bank of a preliminary switch designated by the brushes 101, 102, while the terminals 168, 169 are shown terminating in the bank of a preliminary switch represented by the brushes 166, 167. It will be understood that each of the link circuits 184, 185 and 186, 187 have an appearance in each of the preliminary switches which has access to the selector switch shown in detail, and as above mentioned the first link will have pre cedence in selection over the second link.

A single operating and controlling mechanism is provided for both sets of brushes. The operating magnet 129 carries an armature having two pawls 130, 131. The first pawl 130 is designed to cooperate with the ratchet wheel 147 for the purpose of rotating the upper set of brushes. The second pawl 131 cooperates with the ratchet wheel 148 to rotate the brush shaft 183 carrying the lower set of brushes. A shaft 140 operating cams 132, 133 is controlled by a selecting magnet 138 to determine which of the two pawls of the operating magnet 129 shall be effective in rotating its associated ratchet wheel. Three relays 116, 117, 118 are provided in common to the two operating units of the selective switch and serve to control the cir cuits for creating impulses to drive the se lected set of brushes under the control of incoming impulses from a subscribers dial.

-There is also provided for each of the links 184, 185, and 186, 187 an individual sequence switch for controlling the circuits pertaining to these links. Sequence switch 110 is individual to the link 184. 185, while sequence switch 180 is provided for the link 186,187.

It is believed that a better understanding may be had of the invention by giving a detailed description of the operation of the switch. Consider first that both of the links leading to their respective brush sets are idle and a call is initiated on a subscribers line 100. In any well-known manner the brushes 101, 102 of the individual switch are operated to test the condition of terminals,

such as, 103, 104, to select an idle link circuit leading to selector switch. Inasmuch as the link circuit 18 1, 185 is idle at this time the brushes 101, 102 are positioned upon the terminals 103, 104 of said circuit. A circuit is then completed from battery through the left-hand winding of relay 116, upper right-hand contact 107 (1+2), upper left-hand contact 107 (1+4), terminal 104, brush 102 over the loop of the calling sublscribers line 100, brush 101, terminal 103, upper left-hand contact 106 (1+ 1), upper right hand contact 106 (1+2), right-hand winding of relay 116 to ground. Relay 116 operates and completes a circuit from battery through the winding of relay 117 to ground at the right-hand alternating contact of relay 116. Relay 117 becomes operated and closes a circuit from ground through its outer cont-act, lower right-hand contact 109 (1+3), upper left-hand contact- 109 (1+3) to the test terminal of the individual switch. This ground'potential renders the link circuit 134, 185 non-selectable to other switches. A circuit is also completed from ground through the outer contact of relay 117, lower contacts 174;, (1+3) to the-test terminal 170 for rendering the second link circuit 186, 187 non-selectable during the time the first set of brushes is being operated. Relay 116 also completes a circuit from ground through its left-hand contact, upper right-hand contact 111 (1+4), upper left-hand contact 111 (1), winding of sequence switch to battery. Sequence switch 110 thereupon advances from position 1 into position 2. As the sequence switch 110 reaches position 2 a circuit is closed from battery through the winding of selecting magnet 138, contacts 115 (2) to ground. The magnet 138 attracts its armature 139 and rotates the cam shaft 140. The rotation of the cam shaft llO carries the cam 132 away from the pawl 130 so that this pawl is allowed to move forward into operative relation with the teeth of the upper ratchet wheel 147. At the same time the rotated cam shaft 1&0 carries the cam 133 into engagement with the lower pawl 131, whereby this latter pawl is prevented from engaging the teeth of the lower ratchet 1&8 when the armature of stepping magnet 129 is operated.

The calling subscriber now manipulates his dial 183 to transmit a series of impulses corresponding to the first digit of the called designation. The terminal bank-152, which for the purpose of simplicity is illustratedas consisting of merely a single row of arcuate contacts, may be considered as divided into a plurality of groups. Each of these groups consists of a: small number of terminal sets. The first series of impulses representing the first digit transmitted by the calling subscriberoperates the selected set of brushes to position such brushes in operative relation to the corresponding group of terminals in the bank 152. Upon the first opening of the line circuit in response. to. the first impulse series, relay 116deenergizes and. completes a circuit from ground. through its right-hand alternate contact, inner alternate contact of relay 117, winding of relay 118 to battery and ground. Relay 117 being slow to release. does not deenergize during the transmission of impulses. The slow to release relay 118 energizes in the above circuit and completes a circuit from ground through its inner contact, side switch arm 120 (position 1), winding of the escape mag.- net 119 to battery. The escape magnet 119 becomes energized preparatory to releasing the brushes of the side switch, illustrated within the broken rectangle at the upper part of the figure, upon deenergization. Relay 116 also completes a circuit from ground through its right hand alternate. contact, side switch arm 121 (position 1)., winding of stepping magnet 129 to battery. Magnet 129 attracts its armature and the pawl 130 engages the ratchet wheel 1 17 to advance the brushes 142, 143 and 14% forward one step. For each succeeding impulse in the series, the relay 116 releases and the stepping magnet 129 moves the selected set of brushes forward until they are finally positioned in operative relation to the proper group of terminals.

Following the last impulse of the series, the relay 116 remains energized in series with the calling line for a sufficient interval to permit the slow to release relay 118 to become deenergized. Relay 118 opens the holding circuit of the escape magnet 119, which magnet deenergizes and releases the brushes of the side switchto their second position terminals. In this position of the 7 off normal contact 125, contacts 136 and'135 to ground. Itrwill noted that the contacts 136 and are arranged to engage one other when the shaft 140 is rotated by the selecting magnet 138. Furthermore, the secondary oft normal contact 125 is closed at this time and is arranged to be opened imme diately that the brush shaft 141 is rotated to advancethe brushes in their first secondary movement. The secondary ofi'normal contact 125 associated with shaft 141 and the secondary off-normal contact 137 associated with shaft 183 may-take the form of a contact arrangement operatedby an appropriately cut cam such for instance as that shown inthe patent to Craft 1,117,553 or -the patent to Holmes and Craft, 970,821. The escape magnet 119 operates in the. circuit above traced preparatory to releasing the side switch into its third position. With the side switch in position 2 a circuit is completed from battery through the winding of the stepping magnet 129, side switch arm 121 (position 2), contacts 127, 128 to ground. The stepping magnet 129 interrupts its own circuit by means of the contacts 127, 128 and rotates the ratchet 147 to advance the brushes 142, 143 and 144 over the selected group of terminals in search of an idle one. It will be assumed that busy terminals are identified by the pressure of ground potential thereon. ()n the first secondary step of the switch the oil normal contact is opened but the escape magnet 119 remains energized provided the first set of terminals, on which the brushes are now standing, are busy. The circuit for holding the escape magnet 119 energized now leads from battery through the winding of said magnet, side switch arm 120 (position 2), contacts 113 (2), brush 144 to the busy testterminal.

Nhen the brushes encounter an idle terminal the holding circuit of the escape mag net 119 is opened and this magnet deenergizes to release the side switch into position The circuit of the stepping magnet 129 is thereby opened and the brushes are brought to rest in contact with the idle terminals in the bank 152. lVith the side switch in position 3 a circuit is closed from ground through the side switch arm 122 (position 3), upper right hand contact 112 (2), lower left hand contact 112 (2+4), winding of sequence switch magnet 110 to battery. The sequence switch 110 moves out of position 2 and into position 4. As soon as the sequence switch 110 reaches position 3 the lower right hand contacts 106, 107 are closed to extend the calling subscribers line through over the link circuit 184, 185 and brushes 142, 143 to the next switch beyond. In any well known manner the extension of the connection to the next switch serves to apply busy ground potential to the third conductor, whereby a circuit is closed from battery through the winding of relay 126, test brush 144 to the busy third conductor. Relay 126 operates in this circuit prior to the time that sequence switch 110 reaches position 4. hen sequence switch 110 leaves position 2 it opens its upper right-hand contacts 106, 107, severing thereby the holding circuit of relay 116. Relay 116 on deenergizing closes the above traced circuit for relay 118. Relay 118 attracts its armatures and after the necessary interval following the release of relay 116 the slow to release relay 117 retracts its armatures. lVith relay 117 decnergizcd and the slow to release relay 118 energized, a circuit is closed from ground through the righthand normal contact of relay 116, inner normal contact of relay 117, outer alternate contact of relay 118, winding of release magnet 124 to battery. Release the winding of release magnet 153, normal contact ofrelay 126, primary off normal contact 179, contacts 114 (4) to ground. The release magnet 153 energizes and locks up in a circuit including its contacts 156 and 157. The magnet 153 rotates the restoring shaft 181 to disengage the holding pawl from the ratchet 147, thereby permitting the brushes 142. 143 and 144 to be restored to normal as by means of a retractile spring not shown. When the brush unit ti has completely returned to its normal position the primary off normal contact 179 opens and the release magnet 153 is permitted to deenergize. The release magnet 153, on operating, also closes a circuit from ground through the contacts 154 and 155, lower right-hand contact 112 (4). lower left-hand contact 112 (2+4), winding of sequence switch magnet 110 to battery ad vancing the sequence switch 110 out of posi- W tion 4 and into its normal position 1.

It will next be assumed that a second call is initiated during the time that the first set of brushes are in their operative position extending a call over the upper link circuit. The subscribers line which initiates the second call is extended by way of brushes 166 and 167 of an individual line switch to the terminals 168 and 169 of the secondary link circuit 186, 187. Inasmuch as the first set of brushes has been completely operated the test terminal 170 is rendered idle by reason of the fact that the slow to release relay 117 has retracted its outer armature. Consequently, the second link circuit 186, 187 is seized and the calling subscribers line 165 is extended by way of sequence switch contacts 171 and 172 to the windings of relay 116. Relay 116 operates and causes the energization of relay 117 as 1 above explained. Relay 116 also completes a circuit from ground through its left-hand alternate contact, upper right-hand contact 111 (1 to 4) of sequence switch 110, lower left-hand contact 111 (4), contacts 175 (1) of sequence switch 180, winding of said sequence switch to battery. Sequence switch is energized in this circuit and driven out of position 1 and into position 2.

The subscriber of the second calling line Ill) 165 now operates his transmitter to send a series, of impulses corresponding to the first digit of the'desired number. This time the relay 138 remains deenergized, its circuit having been opened .when sequence switch moves out of position 2 to open contact 115, and consequently the lower stepping pawl 131 is placed in condition to engage the ratchet 148 to rotate the lower set of brushes 149, 150 and 151. In response to the first impulse of the series, relay 116- deenergizes and completes a circuit as de-- scribed for the slow to release relay 118. Relay 118 causes the energization of the escape magnet 119 over the above traced circuit. When the. last impulse has been sent and the brushes 149, 150 and 151 driven into operative relation with the desired group of terminals, the relay 116 maintains its armature attracted for an interval sufiicient to permit the deenergization of relay 118. Relay 118 causes the release of the escape magnet 119 and the side switch is advanced into position 2. )Vith the side switch in position 2 a circuit is immediately established from battery through the wind; ing of escape magnet 119, side switch arm 123 (position 2), the secondary off normal contact 137, contacts 134 and 135 to ground. It will be noted that the contacts 134,135 are closed when the shaft is in the position for selecting the lower set of brushes. The escape magnet 11 9 energizes preparatory to releasing the side switch into its third position as soon as an idle trunk has been found by the brushes 149, and 151. WVith the side switch in position 2 the above traced circuit is completed for stepping magnet 129 which interrupts its own circuit and advances the brushes from one set of terminals to another in search of an idle one. On the first secondary step of the brushes, the ofi" normal contact 137 opens to open the circuit of the escape. magnet 119. This magnet, however, remains energized provided the first set of terminalsare busy bymeans of av circuit from battery through the winding of'said magnet, side switch arm 120' (position 2), contacts 176 (2) to the test brush 149. As soon as an idle set ofterminals have been found, no ground existing thereon, the above traced circuit for the escape magnet 119 is opened and this mag.- net releases the side switch into position 3. In position?) a circuit is closedir'rom ground through the side-switch arm 122 inits third position, upper right-hand contact 177 (2), lower left-hand contact 177 (2+4), winding of sequence switch magnet 180 to battery. The sequence switch 180 is driyen into position 4. As sequence switch 180leaves posi tion 2 the holding circuit of relay 116 is opened and this relay decnergizes and causes in the manner above explained the des re, Qt c rcuit or the r lea e mas- 1 ,saaaso 124 which restores the side switch to its normal position. As the sequence switch 180 reaches position 3 it extends the calling subscribersline over lower right-hand contacts 171 and 172, link circuit 186, 187 and brushes 150, 151 through to the succeeding switch. A ground potential is immediately applied from the succeeding switch to the test brush 149 causingthereby the energization of relay 164. Relay 164 operates and opens its contacts prior to the time that sequence switch 180 advances into position 4 to close its contacts 178.

After conversation has ceased and the subscribers have replaced their receivers to the switch hooks, the busy ground potential is removed from the test conductor in the usual manner and relay 164 deenergizes.

'R-elay 164 completes a circuit from battery relay 164, contact 163, contacts and 162 to ground. The restoring shaft 182 is 1'0- tatedand pawl 146 disengaged from the ratchet 148 to permit the restoration of the brushes 149, 150 and 151. At the time the release magnet 158 attracts its armature it also closes from ground through the contacts 159 and 161, lower right-hand contact 177 (4), lower left-hand contact 177 (2+4), winding of sequence switch 180 to battery driving sequence switch 180 out of position 4 and into its normal position 1. All apparatus has thus been completely restored to its normal position ready for use in connection with subsequent calls.

)Vhatis claimed is:

1. In combination, an automatic selective switch having a plurality of movable brush sets, a plurality of telephonic link circuits individual to each set of brushes for extending connections to the switch, a motor magnet common to said brush sets, and means dependent on the link circuit over which a. connection, is. extended to the switch for rendering the common mechanism eliective to switch having a plurality of sets of movable brushes, a plurality of telephonic link circuits individual to each set of brushes for extending connections to the switch, a. motor magnet arranged in common to said sets of brushes for driving any one thereof, a selecting magnet for associating the motor magnet with the proper set of brushes, and means dependent on the link circuit over which a connection is extended to the switch for controlling said selecting magnet.

4C. In combination, an automatic selective switch having a plurality of sets of movable brushes, a plurality of telephonic link circuits individual to each set of brushes for extending connections to the switch, a common step-by-step motor magnet for driving any one of said sets of brushes, and means dependent on the link circuit over which a connection is extended to the switch for rendering said common stepping magnet effective to operate the corresponding set of brushes.

5. In combination, an automatic selective switch having a plurality of movable brush sets, a plurality of telephonic link circuits individual to each set of brushes for extending connections to the switch, an operating mechanism common to said brush sets, means dependent on the link circuit over which a connection is extended to the switch for rendering the common mechanism effective to operate the corresponding set of brushes,

and individual release magnets for each set of brushes for restoring the same to normal.

6. In combination, an automatic selective switch having a plurality of movable brush sets, aterminal bank, each of said sets of brushes being arranged to engage the same terminals in said bank, a link circuit in dividual to each set of brushes for extending connections to the switch, an operating mechanism common to said brush sets, and means dependent on the link circuit over which a connection is extended to the switch for rendering the common mechanism effective to operate the corresponding set of brushes.

7 In combination, an automatic selective switch having a plurality of brush sets, a. telephonic link circuit for each brush set, a selector in which the other ends of said link circuits terminate, a subscribers line, a sender thereat for controlling said selector to select one of said link circuits, a motor magnet common to said brush sets, and means dependent upon the link circuit selected by said selector for rendering said motor magnet effective to actuate the corresponding brush set.

In witness whereof, we hereunto subscribe our names this 20th day of December A. D. 1920.

J AMES L. MOQUARRIE. CHARLES L. GOODRUM. 

